1. Field Of The Invention
This invention relates to an on-line gas-in-oil monitoring apparatus and method, and more particularly to a gas-in-oil monitoring apparatus which extracts certain reducing or combustible gases, such as hydrogen and carbon monoxide, from oil in a transformer or other electrical apparatus and detects the presence and concentration of these gases in the oil substantially simultaneously and subsequently regenerates the sensors.
2. Description Of The Prior Art
It is well known that the operating liquid insulated electrical apparatus, such as oil-filled power transformers can be ascertained by determining what gases and their concentration are dissolved in the insulating liquid. Certain gases such as carbon monoxide and carbon dioxide are given off and dissolved in transformer oil as a result of thermal aging and degradation of the cellulose insulation used in the transformer. Arcing in the transformer oil, energy sparked discharges and severe heating which cause decomposition of the oil, are known to produce larger percentages of hydrogen dissolved in the oil. In addition, large quantities of hydrogen indicate excessive moisture in critical areas of the transformer.
Oil and cellulose constitute the primary insulating components of transformers, therefore their decomposition is indicative of deterioration in the transformer. Analysis as to which gases and their concentration are dissolved in the oil can provide an indication of the status and condition of a transformer and the type and location of the problem. Periodic analysis of the transformer oil is used to determine the condition of the transformer. It is known to extract the gas from the oil in an electrical transformer, remove it from the transformer itself, and analyze it by chromatographic methods, See U.S. Pat. Nos. 4,587,834 and 4,058,373. U.S. Pat. No. 3,866,460, which is incorporated by reference, discloses an oil-in-gas monitor which detects the amount of a predetermined gas-in-oil in an electrical apparatus by measurement of the partial pressure of the hydrogen gas.
There remains a need for an on-line gas-in-oil monitoring apparatus and method that automatically extracts gases from the oil in a transformer or electrical apparatus and can identify the presence and concentration of at least two different gases substantially simultaneously and subsequently regenerate the sensing device.